Utility of the dried blood on filter paper as a source of cytokine mRNA for the analysis of immunoreactions in Plasmodium yoelii infection

We examined the utility of dried blood on filter paper for the source of cytokine messenger RNA (mRNA). Total RNA was isolated from the dried blood of mice infected with Plasmodium yoelii, and cDNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR). As a reference, we extracted total RNA from peripheral blood collected at the same time as the preparation for dried blood. There was no difference in cytokine mRNA expression between the two sources; the dried blood on filter paper and the peripheral blood. Th1 cells, Th2 cells, and monocytes/macrophages derived cytokine mRNAs in the dried blood from infected mice were detected, and the increase of some of the cytokines mRNAs after infection was also observed. These results suggested that the dried blood on filter paper is satisfactory RNA source for immunological examination in field-based studies.